transform: transform the `with` statement

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/src/transform.nit b/src/transform.nit
index dac3c4f..118142a 100644 (file)
--- a/src/transform.nit
+++ b/src/transform.nit
@@ -285,6 +285,57 @@ redef class AForExpr
        end
 end
 
+redef class AWithExpr
+       # is replaced with a do/end and injected calls to `start` and `finish`
+       #
+       # Basically, the following
+       #
+       # ~~~nitish
+       # with expr do
+       #   block
+       # end label l
+       # ~~~
+       #
+       # is transformed into
+       #
+       # ~~~nitish
+       # var x = expr
+       # do
+       #   x.start
+       #   block
+       # end label l
+       # x.finish
+       # ~~~
+       #
+       # The point is that `finish` is called even if the block is escaped.
+       redef fun accept_transform_visitor(v)
+       do
+               var escapemark = self.break_mark
+               assert escapemark != null
+
+               var nblock = v.builder.make_block
+
+               var nexpr = n_expr
+
+               nblock.add nexpr
+
+               var ndo = v.builder.make_do
+               ndo.break_mark = escapemark
+
+               var start = v.builder.make_call(nexpr.make_var_read, method_start.as(not null), null)
+
+               ndo.add start
+
+               ndo.add self.n_block.as(not null)
+
+               nblock.add ndo
+
+               nblock.add v.builder.make_call(nexpr.make_var_read, method_finish.as(not null), null)
+
+               replace_with(nblock)
+       end
+end
+
 redef class AArrayExpr
        # `[x,y]` is replaced with
        #